Life by Bits & Numbers » General

Windows 8 “contracts” what’s the fuss is all about

Inteist — Mon, 26 Sep 2011 21:41:07 +0000

So I just heard about the upcoming “contracts” concept for future versions of Microsoft products (the contracts will probably get propagated at least partially into virtually all Microsoft products like Windows Phone, XBox, Tablet OS versions etc). The general idea seems to be that various applications will be able to share data and communicate otherwise not really disclosing too much about their functionality.

It is exciting news yeah, but why does it so painfully reminds me of Android “intents” system? To me it is exactly the same. Although some sources say it has some ideas similar to what former Microsoft Chief Software Architect Ray Ozzie’s proposed as the “universal clipboard” concept — dating back to 2006. I still find it hard to see how this is different from Android’s intents system. It would be interesting to watch who sues who over that if at all. The huge piles of patents Google and Microsoft have do not make much sense to go to war over this.

It is interesting though to see how one of the most important features/ideas of Android OS gets propagated into other operating systems.

TextMate go to last edit plugin

Inteist — Tue, 03 May 2011 05:54:47 +0000

I have recently started using TextMate. It’s been some time I wanted to give it a try and understand why so many people rave about it but every time I needed to use it, I usually wanted to do something very simple and sometimes I just got overwhelmed by all the options and sometimes I just didn’t want to invest а lot of time into figuring out how to “use” TextMate beyond the most basic stuff.

One of the options I missed and couldn’t find an easy way to do was to go to the last edit. After some searching however I did find a plugin that does that. You can download the go to last edit plugin for TextMate plugin and once you install it, you will have the “go to last edit” awesomeness in your TextMate. Use the⌥⌘J combination to activate the plugin. It uses the “undo/redo” mechanism but this particular plugin solves some problems that some other apple scripts or other solutions that use undo/redo technique had.

Enjoy this plugin and enjoy TextMate, although I actually like my MacVim better for most of the stuff I wanted to use TextMate for . And actually I find Netbeans to be very good for JS, I started using TextMate for JS, but now I almost exclusively use Netbeans. Share your thoughts, opinions and experience with TextMate plugins and with Mac editors in general in the comments.

Foursquare’s use of MongoDB

Inteist — Wed, 15 Dec 2010 08:13:00 +0000

I have been to a presentation by Harry Heyman – the first non founder employee of Foursquare. He presented on the Foursquare’s usage of MongoDB, a rapidly gaining popularity NoSQL database. Quickly – the idea behind NoSQL database that it is not based on a relational model as most traditional databases but rather on a document model.

Harry had many interesting things but the one thing that was especially interesting to me was that they basically run all the DB operations of FourSquare in RAM! Yes that’s right. They employ the extra large memory instances on EC2, running with 64GB or RAM and they shard whenever they start approaching certain limits of RAM.

The outages they had in early October were because they hit the memory limit and the databases started to page in and out the data from the hard drives to the memory and back and this quickly brought them down.

He mentioned that this is however not Mongo’s fault and this would have happened with any database they would have used. Which is interesting by itself because it means that the way the application is engineered – the requirements is that all the data that they operate has to be in RAM for the application to be fast enough. I bet there is a lot of smart engineers working at Foursquare and there has to be a good reason for that and in fact Harry mentioned that they basically have to have almost all the checkins available in memory due to the nature of the queries they have to perform on the data. He also mentioned that when (this seemed more of a “when” rather than “if”) they move to dedicated servers with solid state drives, they should not have that limit anymore because then the hard drives (SSDs) in that case will be fast enough.

For me all this was very surprising and I am still a little puzzled about it and wonder whether there is/was no way of engineering the application so that they don’t have to keep pretty much all their data (about 5 million users and 160 million checkins at the moment), all in RAM.

Slides of the presentation

UPDATE (Dec 15 2010) a few related links:

Official blog from Foursquare

Interesting discussion at YCombinator hacker news

Some notes of Alex Popescu from NoSQL blog

UPDATE (Dec 17 2010) – 10gen posted the video of the meetup

MongoDB and Foursquare video

The foursquare and MongoDB logos are properties of their respected owners.

No related posts.

Facebook is down – funny tweets collection

Inteist — Thu, 23 Sep 2010 21:32:43 +0000

Apparently today Facebook was down for 2 hours and for some even more… I did not pick up long time on this since I do not use Facebook, but just accidentally I wanted something and I tried to load it and boom I got:

Not sure whether this is a localized event I went to twitter to see if others had this problem and man I was in for some good laughs. Here’s the collection of funniest tweets during the time that the Facebook was down:

Ant check out the Twitter trends. How “DNS Failure” sounds to you as a trend – huh?

UPDATE: Apparently it wasn’t just my “original” idea to collect funny tweets, many other websites did so as well, what is interesting that there are about 20-30 different tweets overall which just keep repeating from site to site. Are we short of funny twitter-ers? People obviously do care. Maybe they are just afraid Facebook coming after them in revenge? (just kidding of course, or am I?). Let me know what you think in comments.

The difference between Android and the iPhone illustrated

Inteist — Sun, 19 Sep 2010 18:43:27 +0000

I’ve come across this somewhere. There was no credit, so I can not give the credit here, if you know the origin, please let me know and I will make sure to give proper credit.

And the BlackBerry would go – yeah you can do anything if you have strong enough head that it won’t crack from all the banging out of frustration…

Android vs. iPhone vs. BlackBerry Users

Load cod file to BlackBerry using JavaLoader

Inteist — Sun, 05 Sep 2010 17:42:37 +0000

It is simple to load a BlackBerry application packaged as cod file to your device using JavaLoader.exe. With JavaLoader, you do not have to install the desktop manager if you just want to have an ability to quickly load applications to your blackberry

Connect your BlackBerry to your computer through USB
Open command prompt and navigate to the location of JavaLoader.exe
Run “JavaLoader.exe -u=USB load path_to_your_cod_file” command and you should be all set

It is easier if you have the JavaLoader and the COD files in the same dir because then the command is simply

JavaLoader.exe -u=USB load path_to_your_cod_file

UPDATE: The JavaLoader command will not work if you don’t have the BlackBerry desktop manager installed. You will get an error that the port can not be open.

How to use Apache 2.0 license in commercial products, explained in simple terms

Inteist — Wed, 05 May 2010 18:58:17 +0000

If you were wondering whether you can use apache licensed code in your commercial applications and what do you need to do in order to comply with the license here’s the unofficial simple ans short answer.

You can use Apache 2.0 licensed source code in your project as long as you include the copy of the license in your distribution and provide attribution in an applicable way in your distribution.

The slightly lengthier and detailed (but still very simple explanation) is below, taken from Apache license FAQ

Describing legal documents in non-legalese is fraught with potential for misinterpretation. Notwithstanding the text that follows, the actual text of the license itself is legally binding and authoritative.

That said, here’s what the Apache license says in layman’s terms:

It allows you to:

freely download and use Apache software, in whole or in part, for personal, company internal, or commercial purposes;
use Apache software in packages or distributions that you create.

It forbids you to:

redistribute any piece of Apache-originated software without proper attribution;
use any marks owned by The Apache Software Foundation in any way that might state or imply that the Foundation endorses your distribution;
use any marks owned by The Apache Software Foundation in any way that might state or imply that you created the Apache software in question.

It requires you to:

include a copy of the license in any redistribution you may make that includes Apache software;
provide clear attribution to The Apache Software Foundation for any distributions that include Apache software.

It does not require you to:

include the source of the Apache software itself, or of any modifications you may have made to it, in any redistribution you may assemble that includes it;
submit changes that you make to the software back to the Apache Software Foundation (though such feedback is encouraged).

Some web server administration tips on CentOS and cPanel (but not only)

Using Amazon S3 to serve JAD files for BlackBerry OTA distribution

Inteist — Sun, 04 Apr 2010 18:03:16 +0000

If you don’t want the preamble of why I wanted to serve JAD files from Amazon S3, skip to the second paragraph.

I have recently came across the need to push OTA update of the DailyHoroscope application for BlackBerry. I conjectured that OTA updates have different behavior and thus different impact on the web server. There are still many people using their smartphones in general and BlackBerries in particular over the slower EDGE connections as opposed to 3G, not to mention 4G and/or WiMax. So to download 300K file over EDGE connection in the real usage example can take anywhere between 10 seconds to couple minutes. All this time the webserver’s thread serving this specific client will remain running. So it seems like you (or rather your server) can be in a nasty situation when 1000 users simultaneously or almost simultaneously decide to do the OTA update. Also quick calculation with Amazon WS calculator shows that serving files from S3 would be rather cheap even comparing to renting a cheap VPS for that purpose. My estimate was that the whole upgrade process (considering the fact that almost all the users update from S3) will cost me about $15. And this is independent of the time span. For $15 you could get a very cheap VPS for one month (if you are lucky). So it seemed like a no brainer. It indeed was until I faced a few problems with setting this up which I will cover here so that you don’t have to spend much time looking for solutions if you want to do the same.

Setting up S3 is a breeze. Using it – not so much. It is just like any other service pretty much – when you want to sign up and call sales you are answered immediately but if you have a problem and need customer service, well, you can be on hold quite a while. If you have Amazon account already set up, you can use this account. You will have the option to opt for the payment to any of the payment options (now it seems that this is only credit cards) already on file with Amazon or you could add a new credit card so that your S3 bill is billed separately.

When you signed up, you are almost ready to begin using S3. Once you receive confirmation email which can take a few minutes until your request is processed and billing information verified, you are set to go.

Open your Amazon account dashboard and login with your Amazon account you had or just created
Click on Security Credentials
Under the Access Credentials table, look at the first tab – Access Keys
Next to your access key, will be a column Secret Access Key which will have the secret key hidden from the screen.
Press the Show and your secret access key will be revealed

Now you can use this information to log in to S3 and start uploading files. To access S3 you can use S3Fox from any platform since it is FireFox plugin. You can use CyberDuck if you are on Mac which is an excellent free general purpose FTP client which also supports WebDav and SFTP. If you are on Windows, there is also free and feature rich client CloudBerry. S3Fox is very nice and fast and you do not have to install anything on the system, only plugin for FireFox, but I will be using CloudBerry since we will need to set custom Content-Type for the JAD and COD files and CloudBerry is more feature rich than S3Fox.

Open CloudBerry
Enter your credentials and open your S3 account
Create a bucket – it has to have unique system wide name like a domain name (actually subdomain, because after it is created it is references by http://yourUniqueName.s3.amazonaws.com)
Enter into the bucket and create folders, or just upload the files you want to serve. If you like me want to serve OTA BlackBerry application, you probably want to create a separate folder for each release
After you create the folder, use the ACL (access control levels/list) menu button to open the ACL controls

Using the ACL controls, give “Read” access to “All Users” (note that if you place check mark on the bottom “Apply for all subfolders and files” the permissions will propagate down the tree)

Now the whole world can read the files you uploaded. The problem with BlackBerry OTA distribution is that Amazon does not send the right mime-types in the HTML Content-type header. And this is something that you will need to get fixed before people can actually install your application over the air directly from S3.

The right content types for the the JAD and COD are:

jad - text/vnd.sun.j2me.app-descriptor
cod – application/vnd.rim.cod

So using the custom HTTP headers menu button we will be setting those types for JAD file and all the COD files respectively.

Select your JAD file and click on “Set HTTP Headers” button

You will get the custom HTTP headers dialog:

Select the “Content-Type” field and replace it with the text/vnd.sun.j2me.app-descriptor for the value

Now you can repeat the above step for each COD file individually, or you can select all the COD files and set the headers at once but then you would need to add the “Content-Type” header manually for the right COD mime type – application/vnd.rim.cod. Just use “Add” and in the HTTP-Header enter “Content-Type” and in the Value enter “application/vnd.rim.cod”. You should see something like the following dialog

***IMPORTANT to check the “Keep existing headers” or you will loose all your default defined headers which is not good in most cases.

That’s it, you are DONE! Check that you did everything right by pointing your BB browser to http://yourUniqueName.s3.amazonaws.com/yourReleaseFolder/AppName.jad and make sure that you can install the application from there. If you did everything right it should work.

Overall S3 seems like a very nice (and apparently very cheap) service and anyone who serves lots of static content should consider using it for that purpose. But not everything seems so pink in the world of S3 and I am sure you will face many other small problems and nuances while setting it up as I did for my task. But hopefully if serving BlackBerry application is all you want, you should now have everything to get you started.

No related posts.

BlackBerry Upcoming WebKit Browser

Inteist — Wed, 17 Mar 2010 17:20:57 +0000

RIM has unveiled the new upcoming BlackBerry browser based on the new WebKit engine.

At the New England BlackBerry meetup, Mike Kirkup mentioned that they are doing some neat tricks with precompiling JavaScript through MDS which makes the JavaScript blazing fast. You can see it for yourself in the embedded video.

The new WebKit browser will be available in the next OS release but the upgrade will be limited on per device manner since WebKit browser is quite resource demanding.

Anyways, it’s great news and good job RIM!

Firefox 3.6 fix the tab order to open at the end of the tabs

Inteist — Sat, 13 Mar 2010 18:29:20 +0000

Just upgraded to Firefox 3.6 and I am a little annoyed by the new “feature” of tabs opening next to the tab where you open the new tab from. While this might be convenient to some people, I got used to the “old” way of handling tabs and find myself constantly wondering where this new tab is. I might give it a few more days to see whether I get used to it but in case you are annoyed by that too and want to “fix” this here is how you can disable the new “Insert Related Tab After Current” tweak in Firefox 3.6.

Type about:config in the address bar. Then, if needed click the “I’ll be careful, I promise!” button.
In the filter box – type in: tabs.insertRelatedAfterCurrent
Right-click that about:config entry, and choose “Toggle”

This will convert Firefox back to opening a new tab from a web page on the far right of the tab bar, rather than right next to the tab you opened it from.

If you decide that you actually like it and want to switch back, follow these same steps and toggle the “false” back to “true”.